Developing an ecosystem model of a floating wetland for water quality improvement on a stormwater pond. (1st November 2017)

• Record Type: Journal Article
• Authors: McAndrew, Brendan; Ahn, Changwoo
• Is Part Of: Journal of environmental management. Volume 202:Part 1(2017)
• Page Start: 198
• Page End: 207
• Publication Date: 2017-11-01
• Subjects: Floating wetland -- Stormwater ponds -- Nitrogen removal -- Wetland vegetation -- System model -- Water quality; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2017.07.035
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: An ecosystem model was developed to assist with designing and implementing a floating wetland (FW) for water quality management of urban stormwater ponds, focusing on nitrogen (N) removal. The model is comprised of three linked submodels: hydrology, plant growth, and nitrogen. The model was calibrated with the data that resulted from a FW constructed and implemented as part of an interdisciplinary pedagogical project on a university campus, titled " The Rain Project ", which raised awareness of stormwater issues while investigating the potential application of green infrastructure for sustainable stormwater management. The FW had been deployed during the summer of 2015 (i.e., May through mid-September) on a major stormwater pond located at the center of the Fairfax Campus of George Mason University near Washington, D.C. We used the model to explore the impact of three design elements of FW (i.e., hydraulic residence time (HRT), surface area coverage, and primary productivity) on the function of FW. Model simulations showed enhanced N removal performance as HRT and surface area coverage increased. The relatively low macrophyte productivity observed indicates that, in the case of our pond and FW, N removal was very limited. The model results suggest that even full pond surface coverage would result in meager N removal (∼6%) at a HRT of one week. A FW with higher plant productivity, more representative of that reported in the literature, would require only 10% coverage to achieve similar N removal efficiency (∼7%). Therefore, macrophyte productivity appears to have a greater impact on FW performance on N removal than surface area coverage or pond HRT. The outcome of the study shows that this model, though limited in scope, may be useful in aiding the design of FW to augment the performance of degraded stormwater ponds in an effort to meet local water quality goals. Highlights: An ecosystem modeling approach was taken for sustainable stormwater pond management. A floating wetland (FW) was built and its role in water quality improvement studied. Plant productivity may have a greater impact on FW performance on nitrogen removal. Modeling approach provided insights in designing of FWs for their future applications.